Polar Power...

[apogee_man]

Well, I might as well give away my big secret for the good of the group! 

I'm starting to sound like a damn socialist...

 

In all seriousness, I stumbled up this company while researching DC generators.  This is the direction that I would like to go as long as they're not overly expensive.  I had also been looking at using a forklift motor, but this would be a better solution if it would work.

I'm envisioning a bracket that would attach to the Lister bearing cover using longer bolts, that would be larger in diameter than the flywheel (kind of like a heavy duty flywheel cover) that the generator would be bolted to. 

Direct drive utopia...

I have been planning on contacting the CEO to inquire what they would charge to wind one that would run at lower RPM but have been too busy with other projects.

Alternator has 12 Poles....

Here are the alternator specs (worth the read):

http://polarpowerinc.com/products/alternator/3500&6250alternator.htm

And here is their main website that has good info regarding why to use a DC generator.  Lots of good info buried on this site:

http://polarpowerinc.com/products/generators/index.htm

Any company that sells something THIS cool, obviously has their thinking cap on:

http://polarpowerinc.com/products/generators/6-10kwdiesel.htm

They also do solar including manufacturing their own cells!

http://polarpowerinc.com/products/solar_ele/complete_solar_sys_1800.htm

Finally, check out this cool micro co-generation unit!!!!!

http://polarpowerinc.com/products/generators/cogenset.htm

And no, I have no relation to them.  I simply find the company and their products compelling...

Enjoy!

Steve  

[apogee_man]

Well, there goes that idea....

I found a pricing sheet for just the alternators buried on their site.

Model 6250:

$3700 for qty of 1

$3200 for qty 2 - 9

$3000 for qty 10 - 49

Model 3500:

$2600 for qty of 1

$2100 for qty 2 - 9

$1400 for qty 10 - 49

Even if we could get up into the qty 10 as a group buy, they're still darn expensive....

HUGE bummer!!!!!

I still think this would be the cat's meow if we could make them work though...

Steve   

[listeroidsusa1]

They just about took my idea! I am using a 16.5" ID truck brake drum for my rotating field. It uses 12 permanent magnets. The stator is stationary and is being built up using laminations. Its both a simple and cheap solution! I have the brake drum and the mount already built and am working on the lamination stack.

Mike

[DaveW]

 Â apogee-man -

 Â    Why not drift on over to otherpower.com and learn how to build one for yourself?  You can control your voltage out, rpm needs, current out and just about everything else.  I have built two just for my 48 volt batteries and am happy with the results.  One gives me bulk charge when the sun and wind won't cooperate and the other is used to do my equalizing charge about once a month.

 Â    The others I have made are for different speeds, for wind generators.  The biggest hurdle for me was learning to weld so that I could trust the thing to stay in the air.  But if I can do it at my age anyone should be able to.

 Â    I have made a 2500 watt  48 volt dc generator for about $600 in parts, not counting my labor.  It has pushed over 45 amps into the batteries for half a day at a time without overheating.
 Â   
(Note:  I am not a welder and cannot claim to be one.  So my brothers have told me and so I believe.  But if you paint it well and hang it 60 feet in the air, not many people can see the welds, and after 5 years nothing has fallen off yet.)

[apogee_man]

Mike,

"They just about took my idea!"

Apparently they've been doing it since 1992.

Dangit, I hate it when that happens!

 

Dave,

I'll go check it out.  I'd heard of that site before but have never been there...  Now is the time I guess...

I was very interested in Polar's solution because they are using high power magnets.  I also figured that over the years they'd worked out most of the bugs and the efficiency was up there... 

I certainly don't have the funds required to buy one... 

That having been said, no time like the present to learn I guess and do weld pretty well...

Steve 

[apogee_man]

Mike,

Would you mind contacting me offline?

I have a favor to ask if you'd consider it.

Thanks,

Steve

[Quisp]

Steve,   
if you are looking for a DC generator, you should check out www.hydrogenappliances.com and look at their PMAs (permanent magnet alternators). Under $500.

You can get a hub for a windmill. The one I got from them is capable of generating over 300 amps if I could spin it fast enough. That would take about 25hp... not going to happen with a 6/1, but it's good for charging batteries directly. They also have models that produce lots of power at low rpm.

All the best.

[mobile_bob]

what voltage do you want to run at?
24?  48?  other?

my prototype 24 volt nominal will do 2.9 kwatts all day long at 28.8vdc and 100amps
and 15 minutes at 28.8 and 130amps

my prototype 48 volt nominal will do 57.6 at 75 amps in early testing which works out to ~4 kwatt
and i am fairly certain it will do 5 kwatts continuous by the time i work out a few kinks

the 24 volt version will match any ST head in efficiency, and the 48 volt version has done a couple percent
better in testing so far...

more work to be done.

either of these units could be had for a small fraction of what polar wants for theirs

btw, the 24 volt version is 16 pole, and the 48 volt is a 12 pole unit.

neither is a pm head and either can be controlled with a balmar for 3 step charging control and programmable
for any battery technology.

i studied polar's alternators about 10 years ago, nice stuff, but very expensive
and to get accurate control for battery charging is not as easy as one might think
one would have to have a fully functioning electronic governor and integrate it with another microcontroller
to take full control of battery charging.

not a saturday afternoon project by any means.

unless of course you want to babysit the throttle to manage the voltage,,  but then again
you cannot easily manage the amps via rpm of the engine.

the aircore homebuilt pm alternators such as the otherpower boys build are very interesting, and because you build
it yourself they are easily repaired,, that has a lot going for it in my opinion. i am not convinced that an aircore is as efficient
as a battery charger driven by an engine,, but then again i have not seen really good and accurate test results using one either.

bottom line?
there are a lot of options i would explore before i parted with 2-4 grand for a pm head from polar or anyone for that matter.

btw, i am not a big fan of hydrogen appliances pm alternators, although there are those that seem to really like them.
bob g

[mobile_bob]

Mike:

the brake drum alternators have been around for a very long time, they really came into their own
maybe 10-15 years ago, before the advent of the aircore design. hugh piggot from scoraigwind
was building brake drum alternators 30 odd years ago useing 3/4 ton pick drums and axle stubs.

with the large truck drum you are using, i am left to wonder why settle on 12 pole? unless you want 60hz
at 600rpm?  but the problem them become one of regulation.  i suppose the alternators self regulation might
be good enough to deliver 3 kwatts from a 6/1 and not have too much droop?

if for battery charging, i would got for twice the number of poles or more
wind the stator for 3 or maybe even 6phase (not that 6 phase is a bunch more efficient than 3, but rectification
is easier with the current spread about twice the phases.

if you haven't considered it yet, you might look into skewing the stator laminations, makes for a cleaner sinewave
and a lot less cogging which is a blessing on a hand start engine.

other things that use this design are the fisher paykel washing machines from australia
they are converted by some folks for use as alternators for windpower, different application
but the theory is the same.

should be an interesting project

good luck

edit:

got to thinking, you likely will come in at about 75% efficient, so if you can get 3kwatt out you will have about a kwatt of heat
to dissipate, probably 90% of which will be in the stator.. in a brakedrum alternator getting cooling airflow into the stator will take some
thought.

if you are building a much larger output alternator for a twin or big single the heating will be substantial and difficult to remove in a closed
core design.

the brake drum will also get hot, so use some high temp rated epoxy to mount your magnets with, under heavy loads the eddy currents from back emf will he substantial along with histerysis.

a large brake drum alternator would be kinda cool and maybe even practical

i look forward to your getting it done, tested and some efficiency reports coming in.

bob g

[Quinnf]

  ECC 1:9 What has been will be again,
    what has been done will be done again;
    there is nothing new under the sun.

  ECC 1:10 Is there anything of which one can say,
    "Look! This is something new"?
  It was here already, long ago;
    it was here before our time.

Quinn

[oliver90owner]

List,

For those not so much in the kinow re the windpowered PM generators - they are air cored (and thus, less efficient) to avoid any 'cogging', as the wind turbines need to start turning at low wind speed for better all round operation and the cogging from any iron in the core would make them difficult to get going - lift type (aerofoil) wind generators are low torque, high speed machines.

Also one must avoid temperatures much above a 100⁰C or the magnets may not be, for very long!  Earlier neodymium magnets lost theiir magnetism over about 80 degrees.  The newer ones are OK up to 120.  Probably not so important on the top of a pole in a gale force wind, but cooling airflow might be more important for a high power design, inside an engine shed.  Those magnets are much cheaper now, but not that cheap....

Those earlier Hugh Pigott brake drum designs never got hot anyway, but they used ferrite magnets before the neo's were around, so were not so powerful (still better than the alternatives in those days ).

Regards, RAB

[mobile_bob]

"If I have seen a little further it is by standing on the shoulders of Giants"

isaak newton


"and there really isn't anything new under the sun" 

unknown by me its origins


everytime we think we have a new idea, after looking a bit further we find it has all be done before by someone, time after time.

standing on the shoulders of giants?

i'm just happy to dabble around in their shadows
(that last one is mine, er... i think its mine?)



bob g

[listeroidsusa1]

It is true that there really is not much new. I got the idea of the brake drum design from an old electrical engineering book I have that was written around the turn of the century. They had a lot of the multiple pole machines set up for mill work described. I find these projects very interesting. It is rather amazing that the pool of knowledge that exists today makes building some of these machines common place where in the past it was a specialty and proprietary knowledge that made it possible to build one. I've always got a project going it seems. As a machinist, electrician, former motor winder, and mechanic each modality feeds another and keeps life interesting!

At least it fills the time while shop work is slack. According to a government report of all of the counties in the US the county I live in is rated 13th worst in this economy. This was front page news a couple of weeks ago in our local paper. Even our state Employment Security Commission only had TWO jobs listed available in our county, and they were for RN's for the government. No local jobs of any kind were listed.

[mobile_bob]

its pretty bad when you can't even buy a job, even if you have the money to do so.

good luck with your project, i look forward to your results

bob g

[apogee_man]

Well, thanks for all of the interesting info thus far!

I have two different engines, both with different purposes in mind.

The Lister CD (8 hp) will be the primary mover for most of the time.

The Lister CE twin (14 hp) will be available when I need more current than the smaller one can provide.  The goal, due to fuel consumption, will be to not need to use it that often.

Neither engine has been reassembled yet, but will be soon (I bought them in parts).  Need to get some other projects finished up first...

The end goal will be to move to someplace out of town and do the off grid thing.

The three options that I've been considering were high voltage DC (~120 vdc), low voltage DC with battery bank (~48 vdc) or a standard ST setup.

I was attracted to the low voltage DC concept because it would allow the use of an inverter that would eliminate the power pulsing.  I also preferred the 48 volt setup because the battery bank could be used without the need to run the genset all of the time.  Further, it would allow automatic starting via the battery bank if the correct motor/generator were used. (that's why I was looking at forklift motors)

I have been playing with the idea of the high voltage DC setup because I could implement it here in town to start learning now.  It would also be fairly easy to buy a grid-tie inverter and perhaps (doubtful) I might be able to recoup some $$$ off the utility bill.

While I like the simplicity of the ST head, if the power ended up dirty or pulsing, it would not be an option for me...  I'd be looking at building some huge flywheel if that were the case...

While the DC setup isn't immune to EMP, and isn't necessarily simple, I do think it would be reliable if implemented correctly.

The eventual goal would also be to incorporate wind or hydro with solar (hopefully both), depending on the piece of property chosen.

This is my dream setup and it will take time to get there...

I was intrigued by the Polar setup because of it being direct drive.  I figured the simpler the better, and perhaps it also might be more efficient, however I haven't researched that aspect of it.

That's the dream...

Steve